1. Field of the Invention
The present invention relates to a compound containing an imido group, a solution of the compound containing an imido group, and a method for producing of the compound containing an imido group.
In particular, it relates to a compound containing an imido group having a good low temperature curability, a good solubility, a good adhesion to a substrate, and the like in which the compound is obtained by partial hydrolysis of a polyimide molded article as industrial waste, a solution of the compound containing an imido group, and a method for producing of the compound containing an imido group.
2. Description of Related Art
Since a polyimide molded article represented by a polyimide film has an excellent chemical resistance, it is insoluble in various solvents and has high boiling point. As such thermoplastic plastics such as polystyrene, recycling after melting is conventionally difficult to achieve.
For such reasons, when a polyimide molded article needs to be discarded as waste, it is generally buried in the ground or incinerated in spite of high cost. Thus, a problem remains in that it is unsatisfactory in terms of a recycling property or environmental characteristics.
Under these circumstances, various methods have been suggested to chemically hydrolyze and recycle a polyimide molded article to be discarded.
For example, a method including complete hydrolysis of an aromatic polyimide molded article under a pre-determined temperature condition in the presence of alkali at a pre-determined concentration to give aromatic tetracarboxylic acid dianhydride and aromatic diamine as raw materials is known (see, the patent document 1).
More specifically, it is a method of treating polyimide which includes that the polyimide is hydrolyzed at 150 to 230° C. in the presence of 4 to 4.8 times the amount of alkali relative to the polyimide unit to give aromatic tetracarboxylic acid dianhydride and aromatic diamine as raw materials, an aqueous alkaline solution and an acidic solution of them are treated with activated charcoal, a large amount of acid and alkali are added to the mixture, and the aromatic tetracarboxylic acid dianhydride and aromatic diamine are precipitated, separated, and recovered.
Further, a method of hydrolyzing polyimide with a pre-determined structure under high temperature and high pressure condition in the presence of water or alcohol and obtaining it as a low molecular weight product, which is a raw material for polyimide, is suggested (see, the patent document 2).
More specifically, it is a method of dissociating polyimide including hydrolyzing polyimide or a polyamide acid as a precursor thereof under a supercritical condition including, for example, 250 to 350° C. and 10 to 100 MPa in the presence of water or alcohol and obtaining it as a low molecular weight product of aromatic tetracarboxylic acid dianhydride or aromatic diamine, which is a raw material for polyimide.
Further, a method of dissociating polyimide or the like from a polymer-containing solid which contains a metal compound and polyimide and recovering the metal component is suggested (see, the patent document 3).
More specifically, it is a method of contacting, at the temperature of 200° C. or higher, a polymer-containing solid such as polyimide with a polymer-dissociating material containing a solvent which has solubility parameter of 18 (MJ/m3)1/2 or more to dissociate and remove the polymer-containing solid and efficiently recovering the remaining metal component (copper).
Still further, a method of hydrolyzing polyimide as industrial waste by using a large amount of a basic material under low temperature and atmospheric pressure and recovering a pre-determined raw material for polyimide as a recycling material is suggested (see, the patent document 4).
More specifically, it is a method including adding a basic material (e.g., alkali metal hydroxide) capable of producing a hydroxide ion (OH) 20 to 80 molar times the theoretical dissociation amount to the polyimide, hydrolyzing the mixture under atmospheric pressure at a pre-determined temperature (40 to 95° C.), neutralizing the product with an acidic material, and recovering a raw material for polyamide such as pyromellitic acid or aromatic amine.